The invention relates to an electrical line arrangement.
For example, such electrical line arrangements are used as high frequency electrode arrangements of electro-optical modulators, wherein the electrode arrangements are used to supply a voltage across optical waveguides of the modulators for creating a phase shift of the optical waves propagating in the waveguides. For example, travelling wave electrodes are used for supplying a voltage to the optical modulator waveguides as disclosed in the publication “High-Speed III-V Semiconductor Intensity Modulators”, Robert G. Walker, IEEE Journal of Quantum Electronics Vol. 27, No. 3, March 1991.
The impedance of such (broadband) electrode arrangements needs to be adapted to the impedance of a driver unit that is used to supply a high frequency voltage to the travelling wave electrodes. In particular, the travelling wave electrodes are terminated using a terminating resistor for avoiding reflections at the end of the electrodes. In order to provide a terminating resistor that is sufficiently temperature resistant, the terminating resistor will need to have a certain size. This in turn requires that the gap between the travelling wave electrodes enlarges at the end of the electrodes in order to provide space for the terminating resistor. The larger gap at the end of the electrodes, however, may deteriorate the impedance matching of the travelling wave electrodes.